Abstract

Autonomous mobile robots have become a key technology for unmanned planetary missions. To cope with the rough terrain
encountered on most of the planets of interest, new locomotion concepts for rovers have to be developed and investigated. The most advanced locomotion concepts are based on wheels or caterpillars (e.g. Sojourner (NASA) or Nanokhod (ESA)).

These rovers have clear advantages regarding power efficiency and complexity if compared with walking robots. However, they still have quite limited climbing abilities. Typically they can only overcome obstacle of their wheel size.

In the following project, we present an innovative rover concept with 4 oblong track wheels. In the normal running configuration, the rover has 2 oblong wheels each in the front and the rear.

The steering of the rover is realized by synchronizing the speed difference of the front and rear wheels. This allows for high precision maneuvers and even turning on the spot with minimum slip. Each of its wheels comprise of 2 pulleys run over by a timing belt similar to that in a tank. This insures maximum stability and climbing abilities even for very low friction coefficients between the wheel and the ground.

A well functioning prototype has been designed and manufactured in our lab. It shows excellent performance surpassing our expectations. This rover is able to passively overcome unstructured obstacles of up to two times its wheel length and can climb stairs with steps of over 60 cm.With very good stability, this rover is able to passively overcome steps of twice its flipper length, to climb stairs or to move in very rough terrain.

Thus this rover is the perfect candidate for long range planetary missions as well as for operations in environment that are both structured and unstructured like for space construction robotics. Terrestrial applications are also numerous: indoor and outdoor surveillance, ventilating shaft cleaning, mining and construction machines, agriculture, post earthquake assistance or even mine clearance if good sensors appear. In a next step, the robot will be equipped with adequate sensors for fully autonomous operations.